Many different types of pumps, in particular, regenerative turbine pumps, have the capability to deliver fluid from one location to another. Typically, a pump moves fluids from lower pressure to higher pressure, and overcomes this difference in pressure by adding energy to the system. Normally, regenerative turbine pumps add energy to the system by adding centrifugal force and shearing action to the fluid.
Generally, a regenerative turbine pump includes an impeller that has a multiplicity of impeller vanes in series. Unlike many other types of fluid pumps, in a regenerative turbine pump, fluid travels through the impeller more than once by completing multiple revolutions through the vanes. The multiple revolutions of the fluid through the impeller vanes impart a centrifugal force outward to the impeller periphery. Preferably, the centrifugal force creates an orderly circulatory flow of fluid that is imposed by the impeller vanes and creates fluid velocity. The fluid velocity may be turned into kinetic energy that in turn is available to increase the flow velocity and/or pressure of the fluid, depending upon the characteristics desired when the fluid exits the pump. Each time the fluid travels through the impeller vanes, the fluid acquires more kinetic energy which may be converted into increased flow velocity and/or fluid pressure.
Many times, regenerative turbine pumps are used in applications that have high head pressure and low fluid flow characteristics. Generally, in situations with very high head pressure and low fluid flow, the pump is susceptible to leakage. Therefore, very tight internal tolerances and parallelism are typically required between the impeller and raceway to reduce the leakage within the pump.
Some regenerative turbine pumps do not have any adjustable features used in parallel with a selected-fit between the impeller and a fixed raceway to achieve and maintain the tight tolerances required for adequate performance of the pump. Generally, the raceway conducts fluid into the impeller, and then provides a channel for the liquid to move in as it is propelled and energized by the impeller. However, after use in the field, the impeller and/or the raceway may gradually wear due to frictional fluid flow and increase the clearance between the impeller and the raceway. Consequently, the pump will lose its performance capability and a costly and time-consuming adjustment of the pump clearances is required to regain optimal performance characteristics of the pump.
What is needed is a pump that does not require field adjustment of the pump clearances after installation to maintain desired tolerances between the impeller and raceway. Also, a pump is desired which provides an inexpensive means to eliminate the costly selected fit of the impeller with the raceway. Furthermore, a pump is coveted which is compliant and is self-adjusting.